One known method of forming a plated coating on the surface of a steel plate is to immerse the steel plate in a pot containing a molten metal such as zinc, aluminum, or a zinc-aluminum alloy. Molten metal pot rollers (such as a sink roller) for continuous plating of the steel plate are placed in the pot. However, the molten metal may dissolve and corrode the molten metal pot rollers. One known countermeasure against corrosion is a method of coating the surface of a roller with a protective thermally sprayed coating.
Patent Literature 1 discloses a method of forming a thermally sprayed coating on a molten metal pot roller. Specifically, a molten metal-immersed member having a thermally sprayed layer on the surface of the roller is disclosed. The thermally sprayed layer includes 5 to 15% by weight of Co with the balance being one kind or two or more kinds of tungsten carbide, titanium carbide, niobium carbide, and molybdenum carbide, one kind or two or more kinds of tungsten boride, molybdenum boride, and titanium boride, and unavoidable impurities.
Patent Literature 2 discloses a boride-based cermet thermal spray powder formed of a composite powder composition including B: 2.5 to 4.0% by weight, Co: 15.0 to 30.0% by weight, Cr: 5.0 to 10.0% by weight, and Mo: 3.0 to 6.0% by weight with the balance being W and unavoidable impurities.
Patent Literature 3 discloses a boride-based cermet thermal spray powder formed of a composite powder composition composed of Mo: 30.0% by mass or more, B: 5.0 to 12.0% by mass, Co: 10.0 to 40.0% by mass, Cr: 16.0 to 25.0% by mass, and unavoidable impurities.